Sporotrichosis

Key Features

• Sporotrichosis is a chronic fungal infection caused by organisms of the Sporothrix schenckii complex

• Found worldwide; most patients have had contact with soil, sphagnum moss, or decaying wood

• Infection occurs via skin inoculation, usually on the hand, arm, or foot, especially during gardening

• Disseminated sporotrichosis is rare in immunocompetent patients but occurs in immunocompromised patients, especially those with cellular immunodeficiencies, including AIDS and alcohol abuse

• Significant zoonotic transmission of Sporothrix brasiliensis has been documented in Brazil and Argentina driven by domesticated cat bites and scratches

Clinical Findings

• Begins with a hard, nontender subcutaneous nodule, which later adheres to overlying skin and ulcerates

• Within days to weeks, lymphocutaneous spread along the lymphatics draining the area occurs, which may result in ulceration

• Cavitary pulmonary disease occurs in individuals with underlying chronic lung disease

• Disseminated sporotrichosis presents with widespread cutaneous, lung, bone, joint, and CNS involvement

Diagnosis

• Cultures are needed to establish the diagnosis

• Serologic tests may be helpful in diagnosing disseminated disease, especially meningitis, but usefulness is limited

Treatment

• Itraconazole, 200–400 mg orally once daily, for several months for localized lymphocutaneous disease and mild cases of disseminated disease

• Terbinafine, 500 mg orally twice daily, also appears to have good efficacy in lymphocutaneous disease

• Amphotericin B intravenously, 0.7–1.0 mg/kg/day, or a lipid amphotericin B preparation, 3–5 mg/kg/day are used for severe systemic infection

• Surgery is indicated for complicated pulmonary cavitary disease

• Joint involvement may require arthrodesis

• Lymphocutaneous sporotrichosis has a good prognosis; pulmonary, joint, and disseminated sporotrichosis respond less favorably